John Newson, who has died aged 84, was one of the leading, yet unorthodox, developmental psychologists of his generation. With his wife, Elizabeth, he conducted the most detailed and discussed British ethnographic study of childhood through parents' eyes, which spanned more than 20 years. Their work not only informed three generations of childcare practitioners about the diversity of parenting experiences, but also called mainstream psychology to account.

The arrival of John and Elizabeth's first child in 1955 determined the nature of their academic careers. Having a colicky baby with disrupted sleep patterns, the Newsons found no help from parenting manuals or professional research. Without funding, they set up a study of 700 families in 1958. The aim was to provide what they called a "listening ear", allowing mothers to reflect on their experiences, without being judged. Convention dictated that the interviews be carried out by women. Elizabeth conducted 200 of these herself, and health visitors did the rest. John often looked after their own children – a role that he relished.

The resulting book, Infant Care in An Urban Community (1963, reprinted by Pelican from 1965) was a great success. It secured funding for the continuation of the study when the children in the sample were aged four, seven, 11, 16 and 22. Three books on the study followed: Four Years Old in An Urban Community (1968), Seven Years Old in the Home Environment (1976) and Perspectives On School at Seven Years Old (1977). A final book on the three later ages was written but never published. John's unique role was the statistical analysis. He greatly enjoyed this work despite the punching of cards in the early days and later the need to be encamped in the university computer centre for hours at a time.

The Newsons became the voice of parents, not only of the initial 700 families but also, following joint research conducted with a range of specialists, of parents of children with disabilities. Mainstream psychology tended to either disregard the influence of parents on their children's personalities, or to work within the impersonal confines of learning theory. The Newsons presented a message that many wished to deny – that social class and cultural influences create a diversity of fundamental beliefs about childrearing. While policymakers, parents and pressure groups lapped this message up, the Newsons were academically hard to place – often deemed to be too sociological for psychologists and too psychological for sociologists.

John was born in south London. His parents soon moved to Chingford, Essex, to be nearer to his mother's extended family and their furniture businesses. His uncles, all master craftsmen, encouraged carpentry skills that were to occupy John along with his academic work. After Bancroft's school, John received a London University extension degree in maths and physics in 1948, his study having been interrupted by a commission in the Royal Corps of Signals in the two years following the war.

His military experience allowed John time to read and decide upon a career in psychology. Following a year of statistics teaching, he took a psychology degree at University College London, graduating in 1951. As a mature student, John immersed himself in his major subject, as well as advanced statistics, philosophy and anthropology. He shared this experience with Elizabeth and they were married on the day that their degree results were announced.

John had secured an assistant lectureship in psychology at Nottingham University before being awarded his degree, in part because of his statistical expertise. He was promoted to a chair at Nottingham in 1975. From the early 1970s, he became gripped by the origins of social understanding in babies. He reflected on the nature of the parent's role in what was termed "mother-infant" interaction, writing a sequence of papers about how parents' treatment of the infant as competent allowed the infant gradually to join in conversational exchanges, involving "inter-subjectivity".

John's interest in woodwork influenced his research on how toys stimulate children's development (Toys and Playthings, 1979). He designed toys to be used for educational purposes, was appointed as a design adviser to a toy company, and, with Elizabeth, set up one of the first toy libraries to enhance the development of children with disabilities.

He was the first chair of the developmental psychology section of the British Psychological Society in 1974, and, on the society's centenary in 2001, he and Elizabeth were asked to contribute an essay on their work to the collection Psychology in Britain. Not only did the Newsons run an integrated training programme at Nottingham University for clinical and educational psychologists, but their child development research unit attracted visitors from around the world. They usually came to a lunchtime meeting, with food prepared by John. That so many visitors and former students returned, or continued a correspondence, is a testament to his charm and the persuasiveness of his belief in the need for psychology to treat parents' and children's views seriously.

In retirement, John dedicated more time to his passions for carpentry and sailing, until Parkinson's disease made these difficult. He is survived by Elizabeth, their son Roger and daughters Carey and Jo.

• Laurence John Newson, psychologist, born 10 December 1925; died 15 May 2010